Electrochemical conversion cells, commonly referred to as fuel cells, produce electrical energy by processing reactants, for example, through the oxidation and reduction of hydrogen and oxygen. A polymer electrolyte fuel cell may comprise a polymer membrane [for example, a proton exchange membrane (PEM)] with catalyst electrode layers on both sides. The catalyst coated PEM may be positioned between a pair of gas diffusion media (GDM), and placed outside of the gas diffusion media layers are cathode and anode plates. Alternatively, catalyst coated diffusion media (DM) layers can be used.
There are many components of a membrane electrode assembly (MEA) that can be combined in layers, including an electrode ink layer, a microporous layer, and a membrane layer. During manufacture of a fuel cell, one or more of such layers can be coated successively on a support. More particularly, the layers can be combined using a sequential coating operation including partial or complete drying of one layer before the next layer is applied. The layers can also be made as independent layers (for example, formed on a sacrificial substrate) and later hot-pressed or otherwise bonded. For example, a microporous layer can be formed on a substrate; a catalyst layer coated on the microporous layer to fabricate an electrode; and then the formed electrode hot-pressed or otherwise bonded with a membrane support.
With conventional coating operations, the processes of manufacturing fuel cell components are complex, time-consuming, and costly, especially where the number of component layers is numerous and where there is duplication of coating and drying equipment. Thus, there remains a need for improved methods for manufacturing components of a membrane electrode assembly, and particularly methods that reduce processing steps and costs.